1. Field of the Invention
The present invention is concerned with an improved tuck pointing gun of the type used by homeowners and others in the repair of brick walls or building facades. More particularly, it is concerned with a tuck pointing gun having an improved, internal, reciprocable plunger which is designed to wipingly engage the internal barrel wall and assure that essentially all of the mortar received therein is expelled during use. In addition, the plunger is designed to yield in the event of a flow-preventing blockage of mortar in the barrel, so that damage to the gun is precluded.
2. Description of the Prior Art
Many owners of older houses are faced with the task of repairing or tuck pointing brick or masonry structures, in order the replace deteriorated original mortar between bricks or the like. While professionals can be hired for this task, this is costly and may not be justified if only a small section of mortar needs replacement and repair. In such cases the homeowner will generally attempt to do the job without resort to professionals.
In order to facilitate the task of tuck pointing, application guns have heretofore been provided. Such guns are of well known construction and include an elongated, tubular, mortar-receiving barrel equipped with a removable, apertured tip cap which allows filling of the barrel. In addition, these prior units include a circular, axially reciprocable plunger within the barrel which is selectively shiftable through use of an elongated ratchet rod secured to the rear of the plunger and in engagement with a trigger pawl. In use, the plunger is first withdrawn to a point remote from the forward outlet end of the barrel, and the latter is filled with mortar. The tip cap is then replaced, and the trigger can be selectively actuated for dispensing mortar through the tip cap.
Although tuck pointing guns of the type described are well known, they are fraught with problems. First, in many prior guns the sliding fit between the plunger and internal barrel wall is less than optimum, with the result that mortar can be left on the barrel wall as the plunger is shifted towards the tip cap. If this residual mortar is allowed to dry on the barrel wall, retraction of the plunger can be difficult and require scraping or cleaning of the barrel itself. This same problem can occur if residual mortar is left within the barrel itself when the plunger is at the forward end of its stroke adjacent the outlet end of the barrel. Here again, if this mortar is allowed to dry, problems of smooth operability and/or cleanout are presented.
Another potentially more serious problem common with prior tuck pointing guns is that the trigger mechanism thereof can be damaged in the event of a blockage of flow of the mortar. That is to say, if a lump or other obstruction is encountered during use of the tuck pointing gun (most commonly if such a lump becomes lodged in or adjacent to the dispensing tip), the most common reaction is to exert additional hand pressure on the trigger mechanism in an attempt to force the lump or obstruction through the tip cap. However, this can lead to significant damage to the trigger mechanism, and in fact the latter can become bent to the point where it becomes useless if excessive force is applied.
Prior dispensing guns of the type adapted to receive a self-contained cartridge of mastic or caulk are described in U.S. Pat. Nos. 3,167,219, 2,923,442, 4,022,355, 3,319,841, 2,731,176, and 2,768,768.